In the industry, a digital logic circuit is generally regarded as a high-speed circuit if the frequency of the circuit reaches or exceeds the range of 45 MHZ˜50 MHZ, and circuits working within said range take up a certain percentage (e.g., ⅓) of the entire electronic system. Transmission and reflection of electromagnetic waves are basic phenomena in a high-speed circuit. Specifically, when propagating in a signal line, a signal will be strongly reflected in case of an obstacle. Unreasonable impedance matching may even cause the signal in a circuit to generate a standing wave. The standing wave leads to too strong or weak signal in a certain region, which makes it difficult to receive the signal, in the worst condition, severe signal distortion may occur, a receiver cannot even latch the signal, and signal distortion becomes severer with the increase in frequency of the signal.
In a liquid crystal display panel, a large amount of data needs to be transmitted from a timing controller to a source driver. Differential signal technique is generally adopted in the data transmission process, and a signal propagates in the form of electromagnetic wave in a differential signal line. With a further increase in resolution of liquid crystal display panel, a data transmission frequency is further increased. Currently, the data transmission frequencies in some high-resolution liquid crystal display devices have gone into microwave band (300 MHZ to 300 GHZ). However, the above characteristics of a high-frequency circuit restrict the design of a transmission signal line, as a signal inevitably passes a signal transmitter, a signal receiver and a terminal in the process of being transmitted from the timing controller to the source driver. Impedance mismatch may possibly occur at any one of the signal transmitter, the signal receiver and the terminal. If the impedance mismatch occurs, a standing wave may be generated and thus signal distortion and signal attenuation may occur.